Industrial air valve with electrically operable pilot valve having minimal solenoid loading

ABSTRACT

There is herein disclosed an industrial-type air valve assembly in which poppet-type valve heads have a new and improved selfcompensating sealing lip and are controlled by a new and improved solenoid operated pilot valve. The pilot valve is connected to an operating solenoid in a manner providing a noload gap between a valve stem and a valve head to reduce starting load. The valve stem is supported by plastic-bearing means providing minimal frictional loading to further reduce starting load. The valve stem and valve head cooperate to provide variable force transfer surfaces whereby pressure forces opposing movement of the solenoid armature are varied from a minimum pressure force prior to opening of the valve providing minimum resistance to the armature to a maximum pressure force immediately after opening of the valve to decelerate the armature to an intermediate pressure force to brake the armature as it bottoms.

United States Patent [72] Inventor Harlan R. Cagle 2,980,139 4/1961 Lynn 251/129X Clarkston, Mich. 3,008,683 1 1/196! Fillivng et al. 251/129X [21] Appl. No 880,061 3,469,590 9/1969 Barker 25 l/129X [22] Filed Nov. 26, 1969 3,527,257 9/1970 Kling 137/625.65 Patented June 1,197! P rzmary Exammer-M. Cary Nelson [73] Asslgnee Sahlm gmeenng Company Assistant Examiner-Robert J. Miller Troy Attorne Harness Dickey & Pierce Continuation-impart of application Ser. No. 635,545, May 18, 1967, now abandoned.

541 INDUSTRIAL AIR VALVE wITII ELECTRICALLY 51 i' g g l i OPERABLE PILOT VALVE HAVING MINIMAL a assem Y w P ea 8 a and Improved self-compensatmg sealing lip and are controlled SOLENOID LOADING b d d l t d 1 Th 6 Claims, 4Drawing Figs y anew an Improve so enol opera e p1 ot va ve. e pilot valve 15 connected to an operating solenoid In a manner [52] U.S. Cl 251/129, providing a noload gap between a valve stem and a valve head 7 25- to reduce starting load. The valve stem is supported by plastic- [5 1] Int. Cl Fl6k 31/06 bearing means providing minimal frictional loading to further Field of Search 25 1/129, r duce tarting load, The valve stem and valve head cooperate 596-17 to provide variable force transfer surfaces whereby pressure forces opposing movement of the solenoid armature are [56] References C'ted varied from a minimum pressure force prior to opening of the UNITED TAT PATENTS valve providing minimum resistance to the armature to a max- 2,052,246 8/1936 Ray 251/138 imum pressure force immediately after opening of the valve to 2,609,989 9/1952 Burk1in,, 251/138X decelerate the armature to an intermediate pressure force to 2,821,355 1/1958 Hicks, Jr .L 251/129 brake the armature as it bottoms.

- J2 J j] \xk j? l I i4 2 04 a"; .Z //4- I u i INDUSTRIAL AIR VALVE WITH ELECTRICALLY OPERABLE PILOT VALVE HAVING MINIMAL SOLENOID LOADING This application is a continuation-in-part of my prior application Ser. No. 639,545 filed May 18, 1967, now abandoned.

BACKGROUND AND PRIOR ART This application is a continuation-in-part of my prior application Ser. No. 639,545 filed May 18, I967 now abandoned. In the prior art, poppet valves and solenoid operated pilot valves have been widely used in applications requiring relatively few cycles of operation. In adapting prior art poppet valves and solenoid operated valves to usage in an air control valve unit of the type described in US. PatfNo. 3,474,825 with swinging arm press unloading apparatus of the type disclosed in US. Pat. No. 2,609,776, I have found that the fast operation and repetitive cycling to which these valves are subjected causes excessive failures in both the valving'and the electrical components. In particular, the poppet valve heads, the pilot valves and pilot valve bodies, and the pilot valveoperating solenoids have presented wear problems.

The unloading apparatus comprises a swinging arm which carries an air actuable jaw device between a lowered position adjacent a press cavity andva raised position located upwardly and outwardly from the press. The swinging arm is moved from the lowered position to the raised position by a single acting air operable power cylinder to which high pressure air is selectively directed. The swinging arm is lowered at a controlled rate as the high pressure air is exhausted from the cylinder. The jaw carried by the swinging arm is positively closed and opened, to grip and release a workpiece, by means of a double acting air operable power cylinder to and from which high pressure air is selectively directed and exhausted to obtain the opening and closing movements of the jaw. Ordinarily, with the swinging ami initially in the lowered position, the operational sequence is: (I) extend and close jaw to grip workpiece, (2) swing arm upwardly and carry workpiece from press, (3) open jaw to release workpiece, and (4) return arm to lowered position.

The air control valve unit is connected to a single high pressure air line, extending from a source of high pressure air, through a common inlet chamber in a valve housing containing an inlet and exhaust valve assembly for the single acting arm cylinder, an arm cylinder speed control valve, and a pair of inlet and exhaust valve assemblies for the double acting jaw cylinder. These valve assemblies are sequentially operated to control flow of high pressure air from the common inlet chamber to the arm cylinder and the jaw cylinder to effect the aforedescribed operational sequence.

The unloading device and associated valving are primarily utilized in large factories which have a conventional industrial type high pressure air supply. Such an air supply is subject to variations in pressure. It is common design practice to assume variations of between approximately 40 psi. and 150 psi. Industrial air valves are commonly designed for operation with lubrication supplied by an oil mist introduced in the air upstream of the valve by special lubrication apparatus. One type of failure of industrial valves is from lack of proper lubricationwhich may result from failure to replenish oil in the special lubrication apparatus or by failure of the lubrication apparatus itself. Of course, failure of industrial valves is highly objectionable not only because of the cost of maintenance or replacement butalso because of the resulting interruption of production.

In the prior art, industrial air valves of the present type have been rated as having approximately a 10 to 14 million cycle life expectancy while the solenoids utilized to operate the pilot valves have been rated as having approximately a to million cycle life expectancy. In actual practice, many of these valves and solenoids fail far in advance of the expected life expectancy.

SUMMARY OF INVENTION It is the primary purpose of this invention to provide a new and improved industrial air valve including an electrically operated pilot valve assembly for use with apparatus repetitively cycled through relatively short operational cycles over long periods of time. i

I have discovered that many industrial air system parts requiring sealing means, such as valve heads, plugs, plates, bearings, end walls, and pistons, heretofore made of machined metallic parts and mounting separate sealing means, such as O-rings, packings, wipers, and the like, may be advantageously made in one piece from a plastic material such as a fluorocarbon polymer. Furthermore, in adapting one-piece plastic parts for use in industrial air systems, I have discovered that exceptionally effective seals can be provided by integrally forming air pressure actuable sealing lips on a one-piece part in a new and improved manner providing for self-compensation for wear in use over exceptionally long periods of time.

The invention further resides in the provision of a solenoidoperated valve in which the number of parts is greatly reduced, the starting force on the solenoid is greatly reduced, the friction load on the solenoid is greatly reduced, and resistance to bottoming of the solenoid is minimized while reducing the bottoming force. Furthermore, new and improved mounting means have been provided and a manual operator has been incorporated with the solenoid apparatus. As a result of this invention, a solenoid-controlled industrial air valve has been provided which will operate in excess of 70 million cycles without failure.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a side elevational view, in section, of a control valve assembly incorporating the inventive features;

FIG. 2 is an enlarged view of the pilot valve portion of the apparatus shown in FIG. I;

FIG. 3 is an enlarged view of the poppet valve portion of the apparatus shown in FIG. l; and

FIG. 4 is an enlarged view of the poppet valve of FIG. 3 disassociated from the valve bore. 7

DETAILED DESCRIPTION Referring now to the drawings, a control valve unit of the type disclosed in US. Pat. No. 3,474,825 illustratively embodies the inventive features. In general, a control valve assembly 10 comprising poppet valve head portions 12, i4 is mounted in a valve housing 16 for movement of the valve heads between open and closed positions relative to an inletexhaust chamber R8. The general operation of these valve assemblies will be understood by those skilled in the art to which this invention relates and are described in further detail in U.S. Pat. No. 3,474,825 and hereinafter only to the extent required for an understanding of the present invention. Suffice it to say that the control valve assemblies control flow of high pressure air to and exhaust air from opposite ends of air operated power cylinders and are alternately actuated between inlet and exhaust positions.

Control valve assembly comprises spaced valve head members 12, I4 interconnected by a valve stem 58 so as to be operable as a unit between an inlet position, FIG. 1, whereat high pressure air is delivered to the associated power cylinder and an exhaust position (not shown) whereat high pressure air is exhausted from the associated power cylinder. Movement of the valve assembly I0 is controlled by a pilot valve assembly 20. An identical pilot valve assembly 22 controls movement of similar control valve assemblies (not shown). The pilot valve assemblies are electrically operable to alternately connect pressure chambers 24, 26 to a source of high pressure air in chamber 28 and to exhaust whereby the control valve assemblies are alternately moved by high pressure air in the pressure chambers between exhaust and inlet positions. Valve assembly 10 is shown in the inlet position with valve head 12 seated and valve head 14 open. Spring means 30 bias the valve assembly to the exhaust position (not shown) whereat valve head 12 is opened and valve head 14 is seated.

Since the electrically operable pilot valve assemblies are identical, the reference numerals are hereinafter applied to one or the other but not to both and it will be understood that each reference numeral is equally applicable to the corresponding part in the assembly not designated. Pilot valve means 32 and operating means 34 are mounted in a housing 36 having a valve bore 38, an inlet passage 40 and check valve chamber 42, an inlet-exhaust passage 44 connected to pressure chamber 24, and a solenoid cavity 46. An end plate 48 having a manual operator bore 50 and cushion chamber 52 is adjustably fastened to the valve housing by threaded fasteners (not shown) to secure the parts in the positions shown. The pilot valve means comprises a combination bearing and end plug and sealing means member 54, a combination bearing and end plug and sealing means and valve body member 56, a combination operator rod and valve stem 58, a valve head member 60, and a compression spring 62. The operating means comprises an armature coil 64 and an armature member 66 mounted in an annature frame 68. A bore 69 in the frame receives the rod 58. A resilient O-ring member 70 separates the member 56 and the armature frame 68 and acts as a vibration cushion. A manual operator member 72 having an abutment plate portion 74 and a pushpin portion 76 is spaced from end plate 48 by a resilient O-ring member 78 which also acts as a vibration cushion.

In the normal position, shown by assembly 22, the armature is located in an extended position with an abutment plate portion 80 in abutting engagement with abutment plate portion 74 of the manual operator. Referring now to FIG. 2, one end 82 of valve stem operator rod 58 abuts the armature 66. High pressure air (e.g. 80 p.s.i. in the illustrative embodiment) in a rod chamber 84 formed by a bore 85 in the end plug 56 acts on the end 86 of the rod to bias the rod and the armature to the extended position. Rod chamber 84 is connected by a passage 87, formed between the rod 58 and the wall of the bore 85 by the clearance (exaggerated in FIG. 2 for purposes of illustration) of a sliding fit, to an inlet chamber 88 between end plug portions of members 54, 56. Thus, the rod chamber 84 is the same as the inlet chamber with respect to the force effect of the high pressure air on the rod 58 which may be slidably supported in bore 85 or by any other suitable means. The high pressure in the rod chamber 84 and inlet chamber 88 is derived from a high pressure source (not shown) through inlet chamber 28 in valve housing 16, a check valve 89, and inlet passage 40. Sealing lips 90, 92 on the end plugs and sealing means 94, 96 on the valve head 32 close chamber 88 in the normal position. High pressure air in chamber 88 and compression spring 62 hold the valve head in a closed position relative to a passage 98 in a portion of member 56 and seated on an undercut valve seat 100. Passage 98 connects pressure chamber 24 via a passage 102 to an exhaust passage means 104, 105.

When coil 64 is energized, armature 66 is moved from the extended position shown by assembly 22 to a retracted position shown by assembly 20. Simultaneously, the rod 58 is moved from the extended position to the retracted position due to abutting engagement with the armature at 82. Rod 58 is slidably supported in bearing portions of the members 54, 56, which are formed by the bores 85, 98, by an end portion surface 106 and an intermediate narrow width surface 108. The length of these surfaces are minimized to reduce friction. The length of surface 106 is such as to provide sliding support throughout movement of the rod and the length of surface 108 is such as to open exhaust port 105 in the extended position and to close the exhaust port in the retracted position. The reduced diameter portions of the rod 110, 112 adjacent the surface 108 and the enlarged portion 113 of bore 98 serve to reduce sliding friction.

An abutment flange 114 is provided on the rod to engage the valve head and move the valve head to the open position against the bias of compression spring 62 and high pressure air in chamber 88. A flange chamber 116 is formed in the valve head and has a depth substantially greater than the width of the flange so as to provide a substantial gap 118 between the valve head and the flange in the extended position. Thus, the rod and armature are moved a substantial distance under minimum load at the beginning of movement. This arrangement may be referred to as a no-load gap means which in effect provides lost motion means between the rod and the valve head. The only load is that caused by the force of the high pressure air in chamber 84 against the end of the rod (e.g. approximately Am the illustrative embodiment), frictional force between the rod and the valve head, frictional force between the rod surface 106 and member 54, and frictional force between the rod surface 108 and the member 56. When the flange 116 engages the valve head surface 120, the additional load caused by the compression spring (e.g. approximately rain the illustrative embodiment) and high pressure air (e.g. approximately 30 in the illustrative embodiment due to p.s.i. air pressure acting through a relatively narrow annular sealing surface on the valve head in engagement with the valve seat) acting on the valve head is encountered. Valve head 60 is moved to the open position to connect inlet chamber 88 to passage 44. Simultaneously, the exhaust passage means 104 is closed so that high pressure air is delivered to the pressure chamber through passage 44. When the solenoid coil is deenergized, spring 62 is effective to move the valve head to the closed position. Movement of the valve head simultaneously moves the rod toward the extended position due to engagement of surface 120 with flange 114. Also, the armature 66 is simultaneously moved toward the extended position due to engagement of the end of the rod 82 with the end of the armature. When the valve head 60 seats on the valve seat 100, the momentum of the rod and high pressure air, acting in chamber 84 on the end 86 of the rod, move the rod and armature to the fully extended position and establish the no-load gap 118 between the valve head and the flange.

One of the advantages of the present structure is that wear between the abutment plate portion 80 of armature 66 and the armature frame 68 is greatly minimized. As is conventional, the abutment plate portion 66 bottoms against the armature frame in the fully extended position. In conventional valve designs, the armature bottoms with such force as to cause extensive wear and eventual failure of the solenoid. The reason for the reduction in wear and hence increased life of the solenoid in the present structure appears to reside in the pilot valve design which reduces the bottoming force. As may be seen by reference to FIG. 2, the armature 66 starts under essentially no-load conditions due to the gap 118 between flange 114 and shoulder 120 as previously described. The only force resisting movement of the rod 58 and armature 66 is that caused by the high pressure air in chamber 84 against the end of the rod and by friction between the rod and the valve body which is quite small. When the rod flange 114 engages the valve shoulder 120, the armature and valve red are traveling at maximum velocity with maximum force. The arrangement is such that maximum load is applied to the armature 66 upon engagement of rod flange 114 with valve shoulder 120. The maximum load is equal to the pressure in chamber 88 acting on the sealing surface area as measured by the diameter of surfaces 96, and the force of compression spring 62. However, the maximum pressure force is only momentarily applied through the valve head because as soon as the valve opens there is pressure equalization relative to the valve head. The velocity of the armature and its energy is substantially reduced by the maximum pressure force as the valve opens. Thereafter, another lesser pressure force is applied through the valve rod as measured by the diameter of the sealing surface 108. The result is that the maximum force of the solenoid armature is utilized to open the valve and much of the remaining force of the armature is dissipated before bottoming. In effeet, the pressure force varies in accordance with the variations in diameter of the rod end 86, the sealing shoulder 100,

and the sealing surface 1108. In the presently preferred form of the invention, these diameters are approximately three thirtysecond inch, one-fourth inch, and five thirty-second inch, respectively,'so that in operation a relatively small pressure surface is effective prior to opening of the valve, a relatively large pressure surface is effective immediately upon opening of the valve, and a pressure surface of intermediate size is effective after opening of the valve to further retard the armature movement and reduce bottoming force. The advantage of the apparatus is that a solenoid of smaller force may be utilized to open the valve and as a result of the smaller force and the dissipation of force after opening of the valve, but prior to bottoming of the armature, there is substantially less wear on the armature and armature frame. Assuming 100 psi. in the pressure chamber 88, the air pressure forces opposing movement of the armature in the preferred embodiment are 0.69 pounds when the valve is closed, 3.76 pounds upon opening of the valve, and 1.92 pounds after opening of the valve or a pressure variation ratio of approximately 1: 5:3. Thus, pressure differential permits opening of the valve with minimal force, substantially slows the armature during opening of the valve, and then brakes the armature prior to bottoming. With the present design a solenoid rated for a much lesser maximum opening force may be utilized. In the presently preferred embodiment, a Model 02 Industrial Grade Solenoid rated at 5.5 pounds at stroke, as manufactured by Detroit Coil Company under US. Pats. Nos. 2,466,592; 2,665,397; 2,671,187; 3,017,547; and 3,195,024 is employed as the electromechanical actuator. While solenoids of this general type have heretofore probably had a life expectancy of between 5 and 7 million cycles in the aforedescribed environment, such solenoids have been operated more than 70 million cycles without failure in association with the present valve design.

Tests of the pilot valve have shown that maximum wear tends to occur between the surface 108 and the bore 98 on opposite sides of the exhaust passage 104. This wear may be substantially reduced by making the member 56 from a conventional glass filled fluorocarbon resin (e.g. Teflon) in which the tiller comprises one or more additives such as -20 percent glass fibers and 5 percent graphite or molybdenum disulfide.

Another feature of the air valve of the present invention is incorporated in the control valve assemblies by providing onepiece annular valve head members 112 formed of plastic material and having integral sealing means. The plastic material is a low water absorption, high wear resistant material having a low coefficient of friction and good machining characteristics. The material is rigid in thick sections but has sufficient flexibility in thin sections to permit high pressure fluids to deflect thin sections and create fluid seals with adjoining surfaces. Fluorocarbon polymer plastic materials such as tetrafluoroethylene polymer and fluorinated ethylenepropylene polymer appear to be particularly well suited for this purpose. Teflon material as manufactured by the E. l. DuPont Company has proved satisfactory. The presently preferred material is a commercially available mixture of the polymer and approximately 15 to percent glass fibers with 5 percent graphite or molybdenum disulfide.

The sealing means takes the form of a generally axially extending, flexible, annular, sleevelike lip 130 formed by an undercut annular groove 132 extending generally axially into the valve body and having a tapered outer side surface 134 outwardly inclined relative to the longitudinal axis of the valve and providing an outer sealing surface band 136 of substantial axial length toward the end of the lip.

The valve bore 138 is a relatively smooth cylindrical surface which slidably receives the valve head 12. A transverse wall 139 extends across one end of the valve bore. The upper portion 140 of the poppet valve 12 provides a transverse abutment surface 141 which acts as a piston in pressure chamber 21 andextends axially beyond the sealing means to prevent engagement between the sealing lip and the end wall 139. When high pressure air is supplied to the pressure chamber, the high pressure air acts on the valve head to move it parallel to the longitudinal axis of the valve bore against the associated spring 30 to seat a sealing rib 142 on an adjoining valve seat 1144 and to move a sealing rib 145 off of its adjoining valve seat 1416.

High pressure air in the pressure chamber also acts in the undercut groove 132 on the sealing lip 130 to force the sealing surface band 136 of the lip into sealing engagement with the adjoining wall 133 of the pressure chamber. The force exerted on the valve head by thehighpressure air causes the sealing surface of the sealing rib 142 to sealingly engage the adjoining valve seat surface. When the valve head is moved in the opposite direction by the spring 30, a similar sealing engagement is effected between the sealing surface of the sealing rib 1415 and the adjoining valve seat surface 146.

1n the presently preferred embodiment in the unflexed unstressed condition of the poppet valve head 12 as shown in H0. 4, the maximum outside diameter as measured at the outer edge of the flexible lip is 1.1l00.002 inch. The axial length of the groove 13 1 as measured at 152 is nine thirty-second inch and the axial length of the base of the lip as measured at 154 is one-eighth inch. The radius at the base of the groove at 156 is 0.024 inch. The inside and outside lip surfaces 134, 160 extend at an angle of 10 relative to the longitudinal axis of the valve head as measured at 162, 164, respectively. The outer edge of the lip is beveled at an angle of 60 as measured at 166. The diameter of the valve bore 138 is 1.070-00005 inch. Thus, in the flexed stressed condition shown in FIG. 3 the flexible lip is inwardly deflected to provide a substantial axial length of engagement with the valve bore, as indicated at 168, with increasing outwardly directed resilient force in the flexible lip from the base of the lip at 156 to the tip of the lip at 150. As a result, wear of the surface 134 does not cause failure of the valve head due to leakage of air past the sealing lip. Instead, the sealing lip provides self-compensating wear means whereby wear due to such factors as misalignment and sliding friction of the poppet valve head in the valve bore is automatically self-compensated by the resiliently inwardly flexed lip structure. Poppet valve heads having this lip structure have been cycled in an air system without lubrication more than 70 million times without failure which is 10 or more times the average life expectancy of prior art devices.

The angle 16 of the outer lip surface determines the amount of surface engagement between the valve head and the bore wall. At an angle of 25 which is believed to be approximately the maximum angle providing sufficient surface engagement for self-adjusting wear compensation, the theoretical axial length of surface engagement in the illustrative valve embodiment is approximately 0.070 inch. At an angle of 7, which is believed to be approximately the minimum angle providing sufficient flexibility and fatigue strength in the lip, the theoretical axial length of surface engagement in the illustrative valve embodiment is approximately 0.265 inch. By way of example, at an intermediate angle of 16, the theoretical axial length of surface engagement is approximately 0.1 13 inch.

The dimensional characteristics of the flexible lip may vary within the limits required for the necessary strength, resilience, and flexibility. 1n the illustrative valve embodiment the thickness of the lip probably should be less than approximately 0.090 and greater than 0.040 inch. The axial length of the lip probably should be less than approximately threeeighth inch and greater than approximately one-eighth inch. The maximum outside diameter of the lip probably should be less than approximately 1.16 inch and greater than approximately 1.1 1 inch. While these dimensional characteristics are based upon a particular bore size, i.e. 1.070 in the illustrative embodiment, the general relationship of the various dimensions illustrates the necessary dimensional requirements to achieve the exceptional results of the present invention and are believed to be generally relatively applicable to other specific embodiments.

it is intended that the claims appended hereto be construed to cover variations of the illustrative embodiment which embody the inventive principles herein disclosed except insofar as limited by the prior art,

I claim:

l. in the combination of a valve assembly and an electrically operable solenoid device for operation thereof:

a solenoid armature movable between an extended position and a retracted position,

a solenoid coil energizable to move the solenoid armature in one direction between the extended position and the retracted position,

a valve head movable between an open position and a closed position,

a single spring means directly operatively engaged with said valve head and biasing said valve head toward one position, said spring means being indirectly operatively engaged with said armature through said valve head and simultaneously biasing said armature toward the retracted position,

a valve stem operating means floatingly operably associated with said valve head by abutting engagement therewith to move said valve head toward the other position and separable therefrom in the one position and operably assoeiated with said solenoid armature by abutting engagement therewith to be moved by said armature to the other position and to move said armature in the opposite direction between the extended position and the retracted position, and

no-load gap means separating said solenoid armature from said valve head and said spring means in the one position and permitting substantial movement of said solenoid armature before operative association with said valve head during movement of the valve head from the one position to the other position.

2. ln the combination of an air control valve assembly and a solenoid device for operation thereof:

an axially movable valveoperating rod means movable between an extended position and a retracted position,

an axially movable solenoid armature movable between an extended position and a retracted position,

a coil energizable to cause movement of said armature from the extended position to the retracted position,

armature rod-connecting means between said operating rod means and said armature effective during movement of said armature to the retracted position to cause movement of said operating rod means to the retracted position,

an air chamber connectable to a high pressure air source,

an airflow passage selectively connectable to said air chamber to permit flow of high pressure air from said air chamber,

a valve member controllably associated with said airflow passage and movable between an extended open position and a retracted closed position relative to said flow passage,

variable force-loading means biasing said valve member to the extended position and providing a first force holding said valve member in the closed position and a second reduced force after the valve member is in the open position,

rod valve-connecting means between said operating rod means and said valve member effective during movement of said armature to the retracted position to cause movement of said valve member to the retracted position,

and lost motion means associated with said connecting means and separating said valve member and said loading means from said axially movable solenoid and enabling substantial movement of said armature from the extended position to the retracted armature before movement of said valve member begins so as to provide a'no-load start condition for said armature.

3. A solenoid operated valve comprising:

a pressure chamber,

a flow passage connected to said pressure chamber,

a valve seat surrounding said flow passage and facing said pressure chamber,

a valve head associated with said valve seat and movable between open and closed positions relative to said flow passage,

spring means biasing said valve head to the closed position,

valve-operating rod means slidably supported for axial movement between an extended position and a retracted position,

an axially extending bore slidably receiving said rod means,

a loading chamber formed by said axially extending bore and being connected to said pressure chamber to cause high pressure fluid therein to exert an axially directed force on said rod means biasing said rod means to the extended position,

a connecting means on said rod means and an abutment surface on said valve head engageable during movement of said rod means from the extended position to the retracted position to move said valve head to the open position and engageable during movement of said valve head to the closed position to move said rod means from the retracted position to the extended position,

an axially movable solenoid armature movable between an extended position and a retracted position,

abutment means engaging said armature in the extended position and locating said rod means and said armature in the extended position,

an armature coil energizable to move said armature from the extended position to a retracted position and being effective to simultaneously move said rod means from the extended position to the retracted position and to hold said armature and said rod means in the retracted position until deenergized,

said abutment means being spaced from and located relative to said valve seat and said connecting means and said abutment surface to locate said connecting means in spaced relationship to said abutment surface in the extended position thereby providing a substantial gap so that an initial portion of the movement of said armature of substantial length occurs before said valve head is operably engaged by said rod means, and

return means for said rod means and said armature effective to move said rod means and said armature to the extended position upon deenergization of said coil comprising said loading chamber and said spring means, said loading chamber and said spring means acting conjointly to initiate movement of said rod means and said armature toward the extended position,

said spring means acting on said rod means and said armature through said valve head until said valve head is seated and said loading chamber acting on said armature through said rod means and causing movement thereof until said armature engages said abutment means whereat said gap between said valve head and said rod means is established.

4. The invention as defined in claim 3 and said abutment surface formed by a recess in said valve head facing said valve seat and having a depth such as to provide a substantial gap between the abutment surface and the connecting means in the closed position of the valve head and the extended position of the rod means.

5. The invention as defined in claim 3 and comprising:

an axially extending support bore formed in said valve head and slidably mounting said valve head on said rod means for axial movement relative thereto, and

sealing means between said valve head and said rod means preventing flow therebetween.

6. The invention as defined in claim 3 and comprising:

a pair of axially spaced plug members,

said pressure chamber formed between said plug members,

said flow passage formed in one of said plug members,

said axially extending bore formed in the other of said plug members and providing bearing means guidably and slidably receiving said rod means,

and said rod means extending through said pressure chamber and being guidably and slidably supported by said bearing means. 

1. In the combination of a valve assembly and an electrically operable solenoid device for operation thereof: a solenoid armature movable between an extended position and a retracted position, a solenoid coil energizable to move the solenoid armature in one direction between the extended position and the retracted position, a valve head movable between an open position and a closed position, a single spring means directly operatively engaged with said valve head and biasing said valve head toward one position, said spring means being indirectly operatively engaged with said armature through said valve head and simultaneously biasing said arMature toward the retracted position, a valve stem operating means floatingly operably associated with said valve head by abutting engagement therewith to move said valve head toward the other position and separable therefrom in the one position and operably associated with said solenoid armature by abutting engagement therewith to be moved by said armature to the other position and to move said armature in the opposite direction between the extended position and the retracted position, and no-load gap means separating said solenoid armature from said valve head and said spring means in the one position and permitting substantial movement of said solenoid armature before operative association with said valve head during movement of the valve head from the one position to the other position.
 2. In the combination of an air control valve assembly and a solenoid device for operation thereof: an axially movable valve-operating rod means movable between an extended position and a retracted position, an axially movable solenoid armature movable between an extended position and a retracted position, a coil energizable to cause movement of said armature from the extended position to the retracted position, armature rod-connecting means between said operating rod means and said armature effective during movement of said armature to the retracted position to cause movement of said operating rod means to the retracted position, an air chamber connectable to a high pressure air source, an airflow passage selectively connectable to said air chamber to permit flow of high pressure air from said air chamber, a valve member controllably associated with said airflow passage and movable between an extended open position and a retracted closed position relative to said flow passage, variable force-loading means biasing said valve member to the extended position and providing a first force holding said valve member in the closed position and a second reduced force after the valve member is in the open position, rod valve-connecting means between said operating rod means and said valve member effective during movement of said armature to the retracted position to cause movement of said valve member to the retracted position, and lost motion means associated with said connecting means and separating said valve member and said loading means from said axially movable solenoid and enabling substantial movement of said armature from the extended position to the retracted armature before movement of said valve member begins so as to provide a no-load start condition for said armature.
 3. A solenoid operated valve comprising: a pressure chamber, a flow passage connected to said pressure chamber, a valve seat surrounding said flow passage and facing said pressure chamber, a valve head associated with said valve seat and movable between open and closed positions relative to said flow passage, spring means biasing said valve head to the closed position, valve-operating rod means slidably supported for axial movement between an extended position and a retracted position, an axially extending bore slidably receiving said rod means, a loading chamber formed by said axially extending bore and being connected to said pressure chamber to cause high pressure fluid therein to exert an axially directed force on said rod means biasing said rod means to the extended position, a connecting means on said rod means and an abutment surface on said valve head engageable during movement of said rod means from the extended position to the retracted position to move said valve head to the open position and engageable during movement of said valve head to the closed position to move said rod means from the retracted position to the extended position, an axially movable solenoid armature movable between an extended position and a retracted position, abutment means engaging said armature in the extended position and locating said rod means and said armature in the extended position, an armature coil energizable to move said armature from the extended position to a retracted position and being effective to simultaneously move said rod means from the extended position to the retracted position and to hold said armature and said rod means in the retracted position until deenergized, said abutment means being spaced from and located relative to said valve seat and said connecting means and said abutment surface to locate said connecting means in spaced relationship to said abutment surface in the extended position thereby providing a substantial gap so that an initial portion of the movement of said armature of substantial length occurs before said valve head is operably engaged by said rod means, and return means for said rod means and said armature effective to move said rod means and said armature to the extended position upon deenergization of said coil comprising said loading chamber and said spring means, said loading chamber and said spring means acting conjointly to initiate movement of said rod means and said armature toward the extended position, said spring means acting on said rod means and said armature through said valve head until said valve head is seated and said loading chamber acting on said armature through said rod means and causing movement thereof until said armature engages said abutment means whereat said gap between said valve head and said rod means is established.
 4. The invention as defined in claim 3 and said abutment surface formed by a recess in said valve head facing said valve seat and having a depth such as to provide a substantial gap between the abutment surface and the connecting means in the closed position of the valve head and the extended position of the rod means.
 5. The invention as defined in claim 3 and comprising: an axially extending support bore formed in said valve head and slidably mounting said valve head on said rod means for axial movement relative thereto, and sealing means between said valve head and said rod means preventing flow therebetween.
 6. The invention as defined in claim 3 and comprising: a pair of axially spaced plug members, said pressure chamber formed between said plug members, said flow passage formed in one of said plug members, said axially extending bore formed in the other of said plug members and providing bearing means guidably and slidably receiving said rod means, and said rod means extending through said pressure chamber and being guidably and slidably supported by said bearing means. 